FIELD DESORPTION MASS-SPECTROMETRY, FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY AND FAST-ATOM-BOMBARDMENT TANDEM MASS-SPECTROMETRY OF ECHINACOSIDE, THE MAIN CAFFEOYL-GLYCOSIDE FROM ECHINACEA-ANGUSTIFOLIA ROOTS (ASTERACEAE)

The mass spectral fragmentation of echinacoside, a pharmacologically active caffeoyl-glycoside isolated from Echinacea angustifolia roots, has been investigated using different soft-ionization techniques, field desorption and fast atom bombardment (positive and negative ions) mass spectrometry. Both ionization modes are successful in molecular mass determination and furnish approximately equivalent structural information. A fast atom bombardment tandem mass spectrometry approach (negative ions) was developed for the study of the fragmentation pathways and for the detection of echinacoside in crude plant extracts. The results demonstrate the usefulness of this technique for the rapid search of this important caffeoyl-glucoside directly in natural complex matrices.